AMAZON'S CHEAPEST MULTIMETER TEARDOWN: THE DT-830B
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- Опубліковано 9 вер 2024
- Tear down of the cheapest multimeter I could find on Amazon. Purchased the meter to extract the integrated circuit so I could obtain die photos. Surprisingly simple process node!.
As expected the meter is a bit of a safety concern for higher voltages and current.
Die photos here:
www.flickr.com...
Meter here:
www.amazon.ca/...
Reference here:
www.voltagestan...
Still absolutely useful. An outstanding review, even for 2023, but considering it was done 6 years ago it is even more impressive. Thank you!
If you have another one, you should try redo the ohm measurements without touching the probe tips/resistors as it included your body resistance in parallel with the resistors.
It's a common mistake,
that was my first thought too. he has a bad habit of touching the probes with his fingers when taking measurements.
I agree. His doing that pretty much negates his concerns regarding the fact that the probe lead banana plugs aren't fully shrouded. But anyway, who in their right mind connects their probes to the circuit BEFORE they plug the other ends into the meter? It's one of those dumbass regulations that health and safety "gurus" come up with, when they have nothing better to do!
tasmedic the fully shrouded plugs aren't really about the simple case of one wire with probe tips to meter. They're much more about the more complex situations you can get in a lab, where you use banana plug leads for everything from the power supply to a bunch of different meters and also quite often semi-permanent alligator clip leads.
The concern with plugs that are not shrouded, is that should a lead that is connected to a live electrical circuit pull out of the meter, the exposed conductor could touch a person and cause an electric shock. I myself the other day had a high quality meter from a respected manufacturer hung via the same manufacturers magnetic kit. But as I was taking measurements, the lead got caught and the meter fell off the steel rack. If the magnet had a better grip, it possible that a lead would have come out of the meter socket and if that lead was a unshrouded type, it would have been a hazard.
@@tasmedic "negates his concerns regarding the fact that the probe lead banana plugs aren't fully shrouded" I'm laughing...THANX
You don't take readings with you fingers touching both probes.
I do it all the time in 480 VAC service panels. Lets you know the wire is live before having to look at the meter.
The silicon mark is that of Sungine Science Ltd.
Right, they pretty much specialize in measurement/display-combo chips. There was one in an old blood pressure monitor I took apart. I don't think the Omron I replaced it with has one of theirs.
+PanoWorks thanks for the information!
Intersil ICL7106 clone, dead giveaway is the small number of capacitors and resistors around the die, plus the analogue circuitry on the lower left of the chip, where you have all the analogue opamps and transmission gates, and the middle of the chip has the big voltage reference ( the zigzag section in the middle) that makes the digital and analogue ground from the 9V battery. Improved in that they look to have added the functions of the CD4070 XOR gate, normally used to drive decimal points and also do the low battery indication. That uses all the pads on the die to give a single chip implementation.
What is your opinion of Extech or Innova Multimeters?
I was going to buy this meter before i watched your video.
www.tscstores.com/MULTIMETER-DIGITAL-P47500.aspx#.WY6mjVWGMdU
Extech > Extech MN35: Digital Mini MultiMeter
www.extech.com/display/?id=14579
Innova > Innova 3300 Digital Multimeter >
www.canadiantire.ca/en/pdp/innova-3300-digital-multimeter-0251059p.html
these meters are astonishingly accurate - if you measure only the resistor and not your body in parallel.
Also nice is the 200µA range which is missing on many more expensive meters!
This meter is also available in kit form. Nice easy kit and a good way to see exactly what goes into a meter. The kit IS fused and mine was within 1 digit of my good meter without further calibration.
The leads are the fuse!
That multi-meter looks like the Harbor-Freight, which you can get it FREE with purchase. They are good enough for everyday use. I have 3 others that I paid about $25 many years ago, not much better than these. I have about 6 of these free ones, lost count. One in each car, bedroom, studyroom, work bench, again, lost count. One of them had a failed display, missing a few segments, I could still guess the number (I save it for parts). The lead wires are a weak link, the wires inside are very thin, breaks/unsolder easily. But I can fix them easily. No complain from me for these FREE meters.
I got them only for the 9V battery.
@@renzevenir4853 you guys sound like me... free and a 9v.. great to have in a car, small and they work, throw 'em away when the battery dies...
Same meter, yes. I have 6 or 7 of them. I calibrated them for DC volts vs my 3457A. Why? Something to do.
Put 10A through the 200mA jacks and then you will quickly find the fuse, or fuse like device. ;) Looks like a coin toss if it will be a trace on the board or the test leads that fail first..
There is no fuse, your probes will melt. At least mine did.
I expect if you do that, "mr epoxy blob" will jump off the PCB very quickly! Or, you'll find "the fastest fuse on 3 legs" instead!
Why would anyone want to measure high amperage for an extended length of time?
The shunt resistor is the fuse. In my early experiences with multimeters, I bought that multimeter for 5€. I used the 200mA current range to measure the current of a computer fan, and was surprised to see that the fan was gradually slowing down (max current was 180mA) After about 30 seconds, smoke poured out of the multimeter. The shunt resistor (tiny 1/8W SMD resistor) burned completely...
I used these dmm-s for a while and usually replaced tiny shunt resistors on 200 and 20ma scales with standard resistors (@ the 200ma I even used a 5W resistor, stupid-proof, u know...)
Interesting and informative. The fact that it claimed to include a fuse was especially amusing.
I found a DT-832 (no B) at a thrift shop for a couple of bucks. Basically identical to this one, except that it has a frequency counter in the spot where the diode tester is. The diode tester is integrated into the ohmmeter range instead.
I found that mine was off by over 15% so I opened it up and found the trimmer potentiometer, and set it to rights. I use it all the time on my bench because it's all I need for most things, and I'm not fearful of blowing it up.
The additional smd footprint in these cheap multimeters is quite revealing actually. And indeed your die shot is virtually indistinguishable from the good old 7107 - as seen here: commons.wikimedia.org/wiki/File:Intersil_ICL7107_top_metal.jpg - well obviously someone pasted your die-shot there, since it very most probably just is an 7107-clone.
In the old datasheets you can still find a rough image of the die for companies buying the bare die for wirebonding: www.bucek.name/pdf/icl7106,7107.pdf
These were the first complete AD chips with direct LCD/LED drive outputs.
I have two of these from Harbor Freight, they are free so.. perfect for my glovebox lol
Looks very similar to the freebie multimeters you see at Harbor Freight. Only differences are that their branded "Cen-Tech" and that they have a separate power switch instead of an "OFF" position on the mode dial.
You can get these for 100 Rs, with leads and full packaging, or for 60/80 Rs for open box one with no leads or anything, from the electronics streets of India. :) In fact I'm using the "120 Rs" yellow model myself! 😀
I got this new on ebay for 6 bux. .Its sold under a ton of brands. Its fine as a once in a while tool and it can measure 120v ac wall outlets with the included probes just as specified without frying. Other cheap multimeters Ive come accross say they can hanle 120v ac and then fry when you check a wall outlet.
those meters are rated for 10 seconds of 10 amp load. The fuses are usually burn through traces designed to burn at a certain load.
I've got a variant of this DMM, free from harbor freight. I took the one i had apart to compare, a few difference were noted. 1. The variant I have doesn't state unfused on the face, although the 10A side is. 2. Although the layout is identical mine included a fuse that was not bypassed. 3. Some of the silk screening had the "10A" port on the banana jack labeled as 5A.
I've just been working on a slightly newer model of this meter. I think it may actually have an SMD fuse in it. The PDF I found online says it's a 250 ma 250 V fuse and doesn't say where it is but the meter has been around a while and gone through numerous revisions. My suspicions where born from looking at several versions of it. Of course there's no logical standard for the marking of SMD fuses but my prime suspect is marked simply "152". There are a couple of nearby holes that could possibly accommodate one of the tiny littlefuse axial fuses I used to install in two way radio products. I'll have to go to one or two amps instead of 250 mA but if it fixes the meter for even a brief while that'll be worth it to me.
Have the Harbor Freight version of this meter, can confirm it has a fuse.
I couldn't get it fixed so I just went on eBay and bought a Velleman DVM810. It's essentially the same meter but it's a little smaller and was very inexpensive.
Mine came with a fuse and battery for $2. Still I don't know why would you need a fuse since no one crazy enough will try to measure 10 amps with this thing, and even if you accidentally blow one of these, it costs the same as a pack of fuse...
I have a DT-830B but it looks nothing like that on the inside. It also has a 500mA fuse.
i.imgur.com/g6ARMPJ.jpg
Note the silkscreened model number
you have the old models the original came with icl7107 ic
Yes, there are differences, I've watched another review where two DT-830Bs were opened and they look neither alike to one another nor to the one showed in this video.
For efficiencies, its a 2 piece pcb, soldered together. The problem is when you put the leads in, it breaks the steel tubes that are barely soldered on the pcb. Thanks for the die pic, awesome. Your right, its not a microprocessor, just analog traces. Still, I would have thought it would have been an off the shelf die, not a custom made one. Maybe the custom is cheaper in the long run, say...2 mil boards. Surprised for 7 bucks that its that accurate. It does say it has a beeper, but I have never seen one yet.
Look closely at the manual, only the DT-830C, D, and 831 has a beeper, the manufacturer is cheap so they only made one manual for all models...
I have one of these. It works well and is fairly accurate. Better than having no meter. Mine has a 0.5A fuse.
I have one now can I put fuse?
The chip inside is a clone of a ICL7106 or some variant of it, I'm surprised that they don't even use a film integrating cap on it.
I believe you're right. There's a good article on hack-a-day re: the influx of the DT830B's that use that IC. That was apparently the same IC that Fluke used in their early DVM's (Fluke actually stopped buying it and created their own fab line so they could protect their ip) but the design still works very well and the IC's are very inexpensive. The very cool thing that got me on this search is the Hfe function; IE being able to plug a 3 prong bipolar junction transistor in and having the meter give you the current gain. I'm astounded to see that included in a $7 meter. It's probably not all that useful for most people but I'm an old, retired EE (actually designed at Fluke in the 70's and early 80's) and to see this was very cool.
On the outside it looks exactly like the Voltcraft VC404 I bought some 15 years ago at Conrad. The inside it is different though, the blob is the same, but the Voltcraft still has through-hole components ;)
So what is this meter good for?
I call these the "bic lighters" of multimeters, use 'em till they die then toss 'em.
-They give these (red) away free with any purchase @ Harbor Freight Tools, so even though I have higher quality DMM's I have a bunch of these, one in each car.
-Your appraisal of the leads is spot on, other leads do work...the most common failure I see is the leads are so weak they fail even when not in use.
- Using mini grabbers (that have no parallel path thru my body) , my resitance readings are more in line with my "good" DMM's
- very handy to check for continuity and "nominal" voltages, 12VDC in your car 120VAC household...
- I would not attempt any current measurements.
$7.. that is too high.. but when free from HFT, not a bad deal, considering they come with a 9V battery.
Thanx for your perspective
i had one of these, it had both a trimpot that would let you adjust around 3-4 percent on the ranges, plus it was within 2 percent easily from the factory, i guess they have taken that part out and ruined its reasonable accuracy.
Harbor freight often has a coupon for this meter being free with another purchase.
I'd love to see that meter tested at it's rated 500v 10amp, I bet it doesn't even get to 500v before arcing over the range selector
I'd just connect it to my 1kV megger, and watch it dance around the room!
I know this is a late comment, but see the video of me "taking" a high voltage measurement with this meter. You talk about arching? 😂😂😂 ua-cam.com/video/Zxhy5HEjZnI/v-deo.html
Altough this is a very old video and was taken with a potato.
These ubiquitous 830B meters are periodically given away as a freebie at Harbor Freight in red color under the CenTech brand with any purchase and coupon, essentially free - thats about all theyre worth-lol Worst thing is the leads, theres so little wire inside they fail easily at the jacks - I adapted a better set of cheap leads and keep one in the car trunk - you can also just run a better cheap set of leads inside and solder them permanently as the jacks are crap - but you can get some basic use out of them for low AC/DC volts.
not bad for a 5v circuit
I have my 830B like ... 25 years. It have fuse and board is totally different.
Excellent
Bought one of these, it looks similar to a very basic meter Mastech used to make, though the internals are far inferior so it's a very cheap and nasty knockoff. This one may be passable as a backup meter for low voltage stuff but I'd not go anywhere near mains voltages with it!!!
Same meter Harbor Freight Gives away. I have about 7 of them. Why? IDK they were free. The leads are CCA I believe.
I bought the original one made by UNI-T back in 1998. It is completely different inside.
i love your channel!!!!!!
This thing nearly killed me. It blew up on 120V ac. Boss bein' cheap. I just wanted to tell him this could kill him. The guts of this one are slightly different by the terminals. You can see there is a new piece of PCB soldered in there. Mine (my boss') had free standing metal tabs bridging the terminals to the main PCB. They were shorted or arced with 120v.
The Eh Team Soo,you are saying that it can't measure voltages from like power plugs?
Just got mine today with a fuse. It is located exactly where you said it looked like it should go. It appears your example might have not been properly checked on construction.
i got the same one from local cheap store for about 3 euros
because the leads broke on my good one.
works just as good IMO
How did you remove the die? Was it nitric acid?
I found this one on Ali Express' Chinese version for RMB 7 yuan. That is US$ 1. The cost to make this probably less than US$ 0.3.
Real men don't need any fuse .
- a poor 830user 😁
watching your videa I went and got my cheapo yellow Hilux DT-830B, to access the battery it is necessary to remove the back panel, I found in mine a small fuse therein so perhaps the earlier ones did have a fuse. kind regards
That looks like the ICL7107 original old chip die. Analog stuff at the bottom and all the digital stuff on the top. The lines are not even straight like they have been distorted slighly when by some sort of film copy.
Splitting digital and analog is just good design - not an Intercil identifier.
I have bought a new Dt-830d with HV continuously displayed on the screen. Why?
I used to have orange one :P Was newer accurate, so used just to see if something is there...
The 10A range on these meters is pretty ridiculous. The meter will withstand 3 amps safely, which is already very low. But the supplied leads are already melting at 1.5A, so thats pretty much useless.
how to calibrate the meter in such designs? I bought one for cheap and took it apart, but i am unable to find any pots
How did you manage to remove that die from the blob of epoxy? I thought the only way was with fuming nitric acid
Yes, that will be it. Look at other videos on the channel, de-encapsulated ICs feature in many of them.
Comment avoir les explications en français. Merci.
thank you very much!
Bos where is the buzzer
Does anyone know what the difference between 830B an 830??
Just bought the same one. Cost RM10 or about USD 2.50
I have that same multimeter but has Continuity mode.
Side Note: It needs 9v battery to be activated.
It is equal to us $.7 each at Aliexpress chinese website.
thanks for sharing
Anddd i have this multimeter
its 250Rs here
.... Outstanding, as is your standard. A Neanderthal would disagree on the complexity of the die. Can I please have the reference standard information, Thanks Mate.
i got the same one on ebay for £3
I bought 5 of these from Ali Express for about $20 with free shipping.
What was the website you used to calculate clearances?
can a buzzer be installed ?
lt can
HELLO HOW WOULD I CHECK mV ON THAT
I got myself one. Was it worth it or did it die one week in ?
a let down ... there doesn't seem to be any continuity beeper (that is the one i use for most of by DIY) it helps map out a circuit connections to a certain extent !!! ... :( ... I was wondering if a beeper could be modded into it ... anybody here who could help me with the points to solder the beeper ? ...
the operation manual lists ...
options like 'fuse(covererd in this video),
an option to measure temperature (but can't find any marked temp position to set the range switch),
it also lists out buzzer for continuity test but no setting(beeper symbol) on the dial.
i know this is a pretty cheap multimeter but a 'no continuity buzzer' is a no go ... a basic function !!!
Wish there was a way to modd into a buzzer ... hmmmm
nope im searching and no luck
any luck with that?
i'm still searching but nothing!
These multimeters comes with a couple of different models but because the manufacturer is cheap, they only made 1 manual for all models. The DT-830D version has a buzzer, you should look for that model. The one in this video is a DT-830B
Occasionally Harbor Freight gives these away "free" with purchase.
I have one of these. I got it for free and I'm still trying to decide what to do with it.
What's the meter doing these days?
Gooberslot a multimeter is allways useful, even that one. For exemple, to have in a car to measure continuity and voltage. Its soo cheap that you can leave it on car for exemple.
This multimeter is good enought for low voltage measurements, when precision is not important. For exemple checking a AA battery voltage, continuity test to see if a cable is broken, etc.
hah I have one of these
no piezo buzzer in my multimeter... how to add?
Mine also dont have buzzer. Can someone tell me how to add please
Look at the manual, some models like the DT-830D has a buzzer, but the DT830B generally don't.
Something is wrong with your meter
So, that reference standard you mention, where do we find info on it?
www.voltagestandard.com/DMMCheck.html
Looks very good, thanks.
@@electronupdate that page gone, but site still up, so thanks
I'm looking for a multimeter on amazon for doing very basic stuff, and this one actually costs 1.5€ + 1€ of shipping.
About 3 bucks or so.
Btw, according to a review it comes without a battery
i just bought one brand new for less than $1.50
Just my opinion, but meters of this low a quality shouldnt even have an amp range, seems like asking for trouble - the red and black leads ARE the fuses- lol
Just got one of these, apparently the shell is common but the PCB can vary a lot.
Disassembling the multimeter reveals really cheap manufacturing and a bit of what looks like corrosion along some of the traces.
Plus it never worked, the thing just reads nonsense : With an open circuit I get no infinite resistance but fluctuating negative values like -1250 and every other function yields the value -1.
Useless piece of trash.
Came, saw, subscribed. Thank you. :-)
i have this this is okay not bad i got it for 4 doller in my country :)
What the name hot detector sir?
hindi Languge like
I bought it for $2 only, I bought like 6 hhh it's a piece of shit
Parah. Mudah eror..
90% kecewa beli produk ini
I just wanted to know how to find the shorted out wiring , this demo SUCKS
i use more expensive leads, and they work just as good as the one supplied with the multimeter... stop spreading bs, dude...
Both the "meter", as well as the leads are garbage. Perhaps you aren't pushing it's capabilities on either pair of leads, but this thing us just a no go.